1. Field of the Invention
The present invention relates to a charged beam device which observes the surface shape and composition of a sample using a charged beam.
2. Description of the Related Art
In manufacturing processes of a semiconductor device, circuit patterns are formed on wafers by lithography, etching and the like. In order to control the dimension accuracy of the patterns formed by each process and to find defects as soon as possible, inspection of the patterns on the wafers (samples) are carried out after these processes. In such inspection in production lines, it is impossible to inspect all circuit patterns. Thus, in general, a part of the patterns that is important in performance of the semiconductor device is extracted for inspection. On the other hand, it is necessary to improve the inspection accuracy with the patterns of the semiconductor device more complicated and miniaturized. However, an increase in inspection time to improve the inspection accuracy results in an increase in the number of parts on the wafers necessary for inspection. Thus, the throughput of an inspection device is extremely deteriorated. Therefore, it is necessary to satisfy the inspection accuracy and throughput at the same time.
Taking an example of an electron beam inspection device that inspects pattern widths as a scanning electron microscope that is one of general charged beam devices, an electron beam is irradiated onto a wafer to scan inspection regions, and an image is formed on the basis of position information and intensity information obtained by measuring, at each position, the intensity of reflected electrons or secondary electrons generated on a wafer surface by irradiation of electron beams. The pattern dimensions observed on the image are measured.
It should be noted that charged beam devices such as scanning electron microscopes are disclosed in, for example, Japanese Patent Application Laid-Open Publication Nos. H08-306330, H08-031364, 2001-006599, 2001-110347, and H10-154479.